This invention relates to an outboard motor and more particularly to an improved breather arrangement for an internal combustion engine.
It is well known that it is desirable to ventilate the components of an internal combustion engine such as the crankcase chamber and the cam chamber. Frequently, the air circulated through these chambers comprises blow-by gases which pass the pistons and cylinder bore and then flow into the crankcase chamber. A portion of these gases are circulated through the cam shaft chamber for its circulation. The circulated gases are then normally passed through an oil separator so as to extract oil from the gases and the gases are then discharged. The gases may be discharged either directly to the atmosphere or to the induction system for the engine for further burning in the combustion chamber so as to reduce the emission of hydrocarbons and other unwanted components.
In addition to the ventilation, the engine also employs a lubricating system and this involves delivery of lubricant to the crankcase chamber and the cam chamber. This lubricant is then drained back to the oil tank for recirculation. Frequently, the ventilating air return and the oil return is through the same conduit and at times the flow is in opposite directions. This can retard either the flow of oil back to the oil tank or the flow of crankcase gases to the respective chambers.
These problems are particularly acute when the engine is employed in conjunction with an outboard motor. It is normal outboard motor practice to place the engine so that its output shaft (the crankshaft) rotates about a vertically extending axis. When this is done the crankcase chamber does not serve the function as the oil tank and a separate oil tank is required. Thus, lubricant must be drained back to this separate oil tank from both the crankcase chamber and the cam chamber and ventilating gases also must flow between these chambers. This further aggravates the problem of ensuring good ventilation and good oil draining.
It is, therefore, a principal object of this invention to provide an improved breather arrangement for an internal combustion engine.
It is a further object of this invention to provide an improved breather arrangement for an outboard motor.
As has been noted, it is frequently the practice to provide an oil separator for the crankcase ventilation gases to separate oil from the gases before the gases are discharged. The use of such oil separators has obvious advantages, but provides additional difficulties in conjunction with outboard motors. As is well known, the construction of an outboard motor is extremely compact and if the oil separator is positioned externally of the engine, it can increase the dimensions of the engine, particularly the height, which is not desirable.
It is, therefore, the further object of this invention to provide an improved oil separating arrangement for the breather system of an internal combustion engine.